The mangrove forest along the northern Brazilian coast is not inundated during low tide. However, many fish species stay in the mangrove forest during this time. Tidal behaviour strategies are described for fish species that linger in the mangrove forest during low tide. The samples were taken at the end of the dry season (December 1996) and at the end of the rainy season (July 1997). Fish were captured using an ichthyotoxic plant extract (Ichthyotere cunabi). Spatial and temporal fish density and biomass were analyzed statistically. Thirty-six samples were taken with a total density of 2.8 ind m-2 and a total biomass of 17.4 g m-2 distributed among seven families and 14 species. Myrophis punctatus was the most important species in number (1.66 ind m-2) and weight (12.68 g m-2) of all catches. The total fish densities were not significantly different among areas and between months, although, total biomass differed significantly in time and space. The densities and biomass for the three most dominant species (M. punctatus, Poecilia spp. and Gobionellus smaragdus) differed significantly among species. Only the biomass of these species showed significant monthly differences. The only significant main effect on variance in the densities and biomass of M. punctatus were encountered between months. In addition, the factor area was significantly different for the variable number of species.